Anchor bolts for friable material, generally comprises a hollow body with a drilling end, a supporting collar at the other end and an external screw thread. A bolt of this kind is disclosed for example, in the document EP-0 165 674.
To insert a bolt of this type into a friable wall, the bolt simply has to be screwed into the wall without a hole having to be pre drilled in the wall as is the case with numerous other anchor bolts. This greatly simplifies fixing.
With bolts of this type, there is nevertheless a risk of the bolt loosening and therefore accidentally withdrawing from the wall.
The invention aims to obviate this disadvantage.